Classic Mustangs (Tech)Technical discussions about the Mustangs of yester-year.

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That's wrong dude. The value of 0.030" or 30-over is not a multiple that you apply to the original displacement. It's the add'l diamater added to the cylinder when it is bored out.

Quote:

Orig: 66GTKFB
Do the math - 4.030 (the bore) divided by 2 - that number times itself - times pi, 3.1416 - times 2.87 (the stroke) - times 8 (it is an 8 cylinder car, right?) and your answer is -
Remember all that crap they taught you in school - put it to work.

YES! Engine displacement equals the total volume of each cylinder times the number of cylinders. Using your formula:

4.030 (bore) divided by 2 = 2.015

2.015 x 2.015 = 4.0602

4.0602 X 3.1416 (pi) = 12.7555

12.7555 X 2.87 (stroke) = 36.6082

36.6082 X 8 (# of cyl) = 292.8658 cubic inches

Anybody wanna do the conversion to Liters?

And to the OP, my 289 is 30-over (0.030") with 75K miles on the rebuild (from 1986). No problems with overheating (especially once I put a REAL temp gauge in the car)

[EDIT: I caught my formula error as you were typing your message royal68] [EDIT, part II: I wanted to clarify that my motor was bored0.030" not 0.300"]

Do the math - 4.030 (the bore) divided by 2 - that number times itself - times pi, 3.1416 - times 2.87 (the stroke) - times 8 (it is an 8 cylinder car, right?) and your answer is -
Remember all that crap they taught you in school - put it to work.

making this method = 292.87

so now we have 3 answers

__________________
1968 royal maroon convertible, 289 w/T5, 4 wheel SSBC power discs, detroit locker/8" rear, AR TT-II's 16x7, Leather 89GT Seats, lot of my money, other doodads....

Well there's a couple of things going on here.
First, it doesn't matter what the displacement is if you bore the engine .3 over because youhave ruined the block!! Boring is done in hundredths of an inchso the question should be about boring 0.030". That extra zero between the decimal point and the 3 makes a big difference.

Second, the equation for the area of a circle is pi*radius*radius. Radius = diameter/2. So the correct area would be 4.030/2=2.015. So the area would be 12.756 square inches. The reason 28HopUp is close is because 2..015x2.015=4.060, which is close to the diameter of 4.030". This only gives a close answer if the bore is close to 4". Any other bore and you bet big differences in the answers.
The volume of the cylinder would then be 36.61 cubic inches and the engine would be 292.9. Others had the formula right but didn't do the math.
One liter equals 61.02374 cubic inches so divide 292.9/61.02374 and you get 4.80 liters. The 302 is 4.95 liters and is usually rounded to 5.0 liters.

The grades are in after my initial post with the formula:
3 get an 'A'
1 gets a 'B'
1 gets a 'D'
2 get an 'F'
There was one repeat entry. As I said - 'Remember all that crap they taught you in school', evidently not.
Comments Glen?
Jim

By making the program, I only had to do the math once,,, but I already knew the formula from high school,,, Basic geometry,,, determining the volume of a cylinder..... X number of cylinders.... (3.14162 x (bore radius x bore radius) x stroke) x number of cylinders,,,,,

__________________ Building cars is EASY, building cars right is a mite bit harder.

The grades are in after my initial post with the formula:
3 get an 'A'
1 gets a 'B'
1 gets a 'D'
2 get an 'F'
There was one repeat entry. As I said - 'Remember all that crap they taught you in school', evidently not.
Comments Glen?
Jim

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